It is reported that the liquid ring vacuum pump has the advantages of good corrosion resistance, compact structure, energy saving, high efficiency and reliable operation because of its small proportion of materials, high strength and wide corrosion resistance. It solves the drawbacks of the original pump products and is suitable for pumping or pressing air, corrosive gas and slag water, organic and liquid without suspended particles or crystals. It is widely used in chemical industry. Industrial and pharmaceutical industries, such as vacuum suction, vacuum filtration, vacuum drying, vacuum concentration, vacuum evaporation, vacuum distillation, vacuum crystallization and plastic forming.
It is pointed out that, especially for by-product gases such as hydrogen chloride, which often occur in chemical and pharmaceutical enterprises, the use of corrosion-resistant liquid ring vacuum pump can effectively suck and compress these corrosive gases to form by-products such as hydrochloric acid with high concentration, which not only meets the requirements of environmental protection, but also forms a circular economy.
At present, there are many types of liquid ring vacuum pumps on the market. Many customers do not know how to select the type. To this end, EVP of the liquid ring vacuum pump company gives four suggestions on the selection of the liquid ring vacuum pump, hoping to provide some reference for the industry.
Choose the specifications with lower rotational speed as far as possible
It is understood that at present, the same specification of liquid ring vacuum pump in China has a variety of rotational speeds for selection. Among them, the larger size of the pump impeller diameter, so the speed is low, so in order to achieve the same pumping volume, we should try to choose the pump with lower speed, so that the consumption of specific power is smaller, higher efficiency.
In addition, the larger size liquid ring vacuum pump has a long blade, i.e. a long runner, a small curvature of the fluid, a straight streamline, a slowly variable flow, and a small energy loss caused by secondary eddy current and boundary layer.
Consideration should be given to the effect of water temperature
It is reported that the performance curves and technical data of the domestic and foreign technical documents of liquid ring vacuum pumps are obtained on the premise that the inlet water temperature is 15 degrees Celsius. Therefore, when selecting liquid ring vacuum pump, the effect of actual water temperature on gas flow should be fully considered.
EVP, a liquid-ring vacuum pump company, said that the temperature of the supplementary water for most users in China ranged from 25 to 35 degrees Celsius. Therefore, when choosing a pump, the volume of gas on the technical documents should be increased appropriately.
Considering the effect of inspiratory resistance
Because the gas suction location is often in the coal mine, far from the liquid ring vacuum pump (some coal mines reach several kilometers), and the suction pipeline is too long, the suction resistance loss should be fully considered. It can be calculated by the formula for calculating the suction resistance used in the coal mine system. When arranging the pipeline, the thicker suction pipeline should be used to reduce the resistance loss and the right angle elbow should be minimized. To achieve the purpose of improving the efficiency of inspiration.
Selection of Exhaust with Micro-positive Pressure
It is reported that at present, some coal mines have to discharge the exhausted gas far away or compress it into the gas storage tank, and the exhaust pressure is generally between 0.02 and 0.05 MPa G. Because the performance curves and technical data in the technical documents of the liquid ring vacuum pump are obtained under the condition that the exhaust pressure is one standard atmospheric pressure, the influence of the increase of the exhaust pressure and the internal reflux of the pump chamber on the pumping volume should be taken into account in the selection of the pump.
In addition, as the exhaust pressure rises, the shaft power of the pump increases, and the power of the drive should also increase. In this case, the manufacturer should provide the test performance curve and the corresponding technical data in order to fully meet the user’s requirements.